Or perhaps where might the patch install log file be located? I can't seem to find it.
Directory should not be issue here.
From the post, I see that you have followed KB#:KB53306.
I will also suggest to look at KBs #: KB70691 and KB53935.
I suspect that it's either permission issue (I will suggest you to use SA account in ePO \core\config page and run the installer) or db.properties file is corrupted.
If db.prop file is corrupted then I will suggest you to rebuild it.
If you can post McAfeeLogs folder (%temp%) then I will surely look into it and will try to find out what is the reason of failure.
Solved! It was a permission issue, I used the SA account in ePO to connect to the database and the patch installed. I had tried using the SA account before but received an error when testing the connection that the account was not an SQL trusted acount or something similar, can't recall exactly what it was.
Thanks for the help!